1920's vapor system?

Robert O'Connor_3

This thing is driving me nuts, to say the least.

The system is a two-pipe with wet & dry gravity returns (1920s). I want to say it is a vapor sytem.

You see, my father had bought the building about 25 years ago, and he and I maintained the majority of building maintenance operations, including the heating system. I was a little young to understand the system completely, however, my dad had it running like a swiss timepiece, and took to operating/maintaining the system with passion. (partially due, I believe to Dan's help via seminar. thanks Dan!) He passed away about 5 years ago, shortly after a friend (and heating contractor with what I would consider to be good steam knowledge) installed a new peerless boiler for him.

To make a short story long, we are having problems with the system (starting this year) the system is equipped with:

1. Hoffman #76 Vacuum Vents (total of eight at the end of steam mains furthest from the bolier)

2. Three (3) Float traps with Air vents in the dry return mains.

3. Ten (10) Thermostatic Traps piped into the dry returns at the end of steam mains.

4. Some radiators have TRVs. All have thermostatic traps.

5. There is no Boiler Return Trap, Differential Loop or Condensate Pump on the system.

6. Peerless Boiler W/Automatic Water Feed/Low Water Cutoff

Problems:

The main problem is that there are 3 apt. that are served by one main (it happens to be the main closest geographically to the boiler) that does not get steam.

There is a thermostatic trap (acting as a vent?) in the dry return at the end of this steam main.

I have replaced the bellows/seat of this Warren-Webster Trap with a Barnes and Jones Cage Unit.

This trap is within 8 feet or so of a big float-trap with a #76 air vent that is venting. However, this float-trap serves another steam main that is heating thoroughly.

I have also replaced all (10) the dry return traps at the end of steam mains.

I checked the pressuretrol settings which, according to what I've read, were way off!

it's a subtractive pressuretrol which used to be set at:

MAIN: .75
DIFF: 1.5

I changed the settings to:

MAIN: 1.5
DIFF: 1

This made wet steam spew from the main air vents when the system shut down, created a 2psi vacuum at the boiler. I changed it back after a couple burner cycles.

Questions:

1. Should this system be running vacuum vents?
2. Is it a vapor system?
3. What about that crazy pressuretrol setting?
4. Any ideas how to get steam to thos three apt.?
5. When making changes to the Pressuretrol, is it possible for the system to take several cycles before evening out (returning condensate, etc.)?
6. There are two guages on the boiler: 1 pressure in psi and 1 vacuum in psi. The pressure guage (although not very accurate) appears to read under 1/4 psi when the boiler is operating.

My dad's friend is leaving for Mexico tomorrow and, needless to say, I'm up a creek without a paddle. Fortunately it's been a warm week, but I'll have three frozen tenants pretty soon!

Please Help

Robert O'Connor_3

PLEASE HELP!!

Steamhead

This sounds like Vapor

However, those Vacuum vents aren't such a good idea if you're not burning coal. Often they can hold up water that's trying to return, which then could block the flow of steam or air. hange them to regular vents.

If the vents are on steam mains, measure their length and diameter and we can tell you what you need. For dry returns don't use anything smaller than a Gorton #1 or Hoffman #75.

Check the path of air leaving the area that doesn't heat. It should all go into the dry return and then out of a vent.

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Robert O'Connor_3

Got it!!

After a week of reading, testing and tinkering (process of elimination) I've finally figured it out.

The problem turned out to be a clogged wet return. About 16' of 1" pipe. It was attached via two unions. Took it apart, snaked the pipe to remove the obstruction. Hooked up the pipe and had steam in that main immediately!!!!

The condensate had no where to go!!!

Anyway, now that I've got steam through all the mains (and to most radiators) I've got to get the boiler to run longer, because the furthest radiators aren't fully heating and the boiler only runs for maybe 15-20 min. I plan on replacing the old thermostat and making some minor pressuretrol adjustments.

If you have any tips for optimizing this system, they would be much appreciated.

Thanks for trying to help, Steamhead!

Fred Harwood

run time

If the boiler is fired to match the load, and the vents work well, all rads should heat well. If not check your main vents and vent according to main volumes. 15 to 20 minutes to get steam to rads is too long. Check those vents and increase venting as necessary.

Steamhead

Nice job

However, you don't need longer run-times.... you need better venting. After you finish stuffing yourself with turkey, measure up your steam mains as noted before and post the results. We'll help you out as soon as we can waddle back to the computer room.

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Robert O'Connor_3

Happy Thanksgiving

I plan on measuring those mains as soon as I recover from a big turkey dinner with all the fixins (not to mention a few days of turkey sandwiches).

Today, I added SQUICK to the boiler. After draining all that wet return water the other day (to clear the blockage), and adding fresh make-up water, the boiler was surging more than it should. It seemed to make an immediate impact.

I also made some adjustments to the thermostat. I have a feeling that when I moved it (from the caretakers apt. to the basement where it was years ago) the anticipation setting was reset. I can't find the documentation on the older White-Rodgers tstat and don't know what it was set at, however, it looks like the anticipator preset is 5 (16 minutes, 8 on, 8 off). I set it to 15 which I calculated to be 18 on, 18 off). Does that mean the burner will kick off after 18 minutes regardless of temperature? Or that the furnace will run for at least 18 minutes even if it reaches temperature first?

I bumped up the thermostat. The boiler ran for 35 minutes, and still the furthest radiators were not thoroughly hot. However, the boiler was probably short-cycling all night and it will take a couple of days to warm that place up. Imagine how fast those cold radiators are condensing that steam (it got down in the high 20's here in the beautiful city of Detroit last night.

As far as Venting...
I must say, I am reluctant to convert the system from vapor. Changing the vents would immediately make the conversion. I figure it would be an injustice to my dad to do so. Would it help to add more vac-vents?

When he bought it 25 years ago, we went through the entire apartment building with a fine tooth comb as far as heating efficiency. From new storms and tuck pointing to cutting holes in the roof to blow in insulation, we did it all together. He took even more pride in the 'tight' steam system he had nurtured.

We saw our heating bill go from over $20,000/year to just under $3,000 in one year. In fact, the dramatic changes in energy cost savings actually led to an investigation by the local gas utility co.

However, like you said Steamhead, vapor was intended for coal burners, therefore, I think the way in which the boiler cycles would be very important to take advantage of the benefits of vapor/vacuum.

I may be way off on all of this, but it certainly is a learning experience.

I have included a pic of the end of main venting:

Hope you and yours have a safe and happy holiday!

Steamhead

Changing the vents

will not make this system a non-Vapor system. Vapor refers to the extremely low pressure that I'm sure it was designed to run at.

However, the system will not be able to hold vacuum when the old vents are removed. This has nothing to do with Vapor. Believe it or not, this is a good thing with oil or gas firing. Vacuum can do a lot of weird things unless you're burning coal.

The thermostat anticipator is calibrated in tenths of an ampere. Measure the current flowing thru the thermostat circuit (sometimes you can find the rating on the relay or gas valve that the thermostat operates). As a starting point, set the anticipator to match this value. If you get short-cycling, set it to a higher value.

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Robert O'Connor_3

Forgive me for..

my ignorance. I understand where you're coming from now. I guess the only benefit to keeping the vaccum-vents then would be the potential of creating steam at a lower temp? That is, of course, as long as the boiler runs again while there's still a vaccum.

Going downtown to measure some pipes. Have a great weekend.

John Shea

Finally measured those mains!

Hi Steamhead.

I finally got around to measuring those mains and I'm eager to replace those vacuum vents with a faster, non-vacuum vents.

Here's the specs:

Again, gas-fired boiler two-pipe vapor gravity return system w/wet & dry returns (see pics):

2 MAINS:

MAIN #1: 125' long @6" pipe, then it's reduced to 3" for 36'
(the 3" would, I guess be considered a main off the main? is there a technical term for these?)

MAIN #2: 105' long @ 6" pipe, then reduced to 3" pipe for 40'

Currently there are four (4) Hoffman #76 on each main.

There are also 3 Vent traps with one vent each as well.
(see pics)

Sorry about the poor lighting for the pics.

BTW, I know that the vents aren't piped properly, but they have been working without water shooting or any type of hammer. (I guess my dad figured it was easier to deal with that 2 1/4" pipe as opposed to the 3")

Thank you for your time.

Steamhead

You need more venting capacity

Main 1 needs 6 Gorton #2 vents, Main 2 needs 5 Gorton #2 vents. This will vent the mains in a super hurry. Your Dad had the right idea but didn't add as much capacity as we would, knowing what we know today.

As long as the vent manifolds your Dad built remain above the waterline, they should be OK.

The "what is this" photo might be a check valve, especially if it's installed on the return line near a Return Trap.

Let us know how well you do!

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John Shea

Time to get a second job (or raise the rent)

WOW. It really is undervented.

The "what is this" pic is in the return piping 4 ft. from the boiler w/no return trap.

The thing that really gets me is:

How could this system have possibly worked without those Main vents?

My dad fitted those manifolds 20 years ago when he purchased the building. How did it heat before the vents?

Also, just curious, why couldn't all the venting be done at those dry return Vent traps (after passing through risers/radiators etc.? Radiator traps would vent too slow?

I will post my progress as it is made.

Thanks so much Steamhead!

Steamhead

With a coal-fired boiler

the fire burned all day. Once the air was out it stayed out- so what if the venting process took an hour? Many oil conversion men didn't add main vents to the systems they worked on, with the result that these systems heated unevenly.

The Vent Traps only have enough capacity to vent the radiators. You want the steam mains to fill completely with steam before the steam enters any of the radiator runouts. This way, when the main vents close, steam will be available at each radiator runout.

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John Shea

Steamhead

"so what if the venting process took an hour?"

Ahhhhh! You've made it VERY clear!!

Vinegar and vents tomorrow.

Have a Great evening!

John Shea

Still waiting on those Gorton #2s

Hi Steamhead,

I'm still waiting for the 11 Gorton #2s you recomended to come in. I try to get a couple of the Detroit supply houses to start carrying them, but no luck so far.

Just curious, Is one (1) Hoffman #75 (as you also recomended) going to be enough for the dry returns (top of vent traps)?

Thanks

Steamhead

Where

did you order the #2 vents from?

For the dry return, "at least" one Gorton #1 or Hoffman #75. More might help here too, now that I know how big this system is. If one vent on the return is non-vacuum, you could use some of those #76 vents on the return.

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John Shea

I called

Gorton, first. They refered me to a local supply house I've never dealt with. They are the only distributor in the area, however, they only stocked up to #1s.

That said, I thought I'd try to initiate two of the biggest supply houses in Detroit, Atlas Plumbing and Advance Plumbing & Heating, with Gorton. They're due in tomorrow or Friday from Atlas, but I think he went to another distributor for them (maybe the one Gorton recomended).

I am going to mention something to the owner at Advance about Gorton. I haven't even used them yet and I'm already sold. It just makes too much sense to vent more rapidly.

Speaking of #76s. There's a little dust cap on the end of those. I unscrewed the dust caps and removed the little sheet metal 'vacuum lids' (for lack of a better term) on all the existing vents.

Can't wait for those Gortons though! I will keep you posted.

On another note...

I did a heat loss for the first time on the building today and I'm not extremely happy about the results. I was prompted by seeing that the boiler wouldn't build more than 4 or 5oz. of pressure.

A local contractor (we use regularly) installed the boiler 7 or 8 years ago and I'm trying to come up with a diplomatic way to talk boiler sizing with him. I feel I could be opening a can of worms here.

The boiler's rated for 1,500,000 btu output. The heat loss I calculated was:

with 1.33 pickup factor - 1,764,505
with 1.5 pickup factor - 1,990,044

There are strategically placed TRVs, but I don't know when they were installed. (before or after this boiler install) Or whether the boiler could have been sized smaller with the TRVs in mind. It doesn't seem like too good of an idea to me.

I don't know what to do. It seems without more than 4 ounces at the boiler, I'll never get good distribution.

Steamhead

Was that output rating

"Gross Output" or "Net Output"? If the latter, the pickup factor is already built in, so if there's that much actual radiation or less you should be fine.

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John Shea

I will check in the morning, but...

assuming it's sized OK, what could explain the inability to build pressure then?

Steamhead

Maybe

a leaky trap somewhere? The worst-case would be if the boiler had a hole in it above the waterline- but I doubt it's that with such a new boiler.

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John Shea

Nope

Gross Output is 1,493,100
IBR in btu/hr. is 1,139,000


Gee. No wonder the building's been hard to heat for the last 8 years. Seems I'm about 200,000 btus short of a properly sized boiler. I'm not sure if the radiators with TRVs would make up this shortfall.

I think what happened was my dad located a slightly used boiler at a great price that was 'just enough' (maybe not) to heat the place.

Will those Gortons even be a factor now? Any suggestions as to optimizing the system short of removing a bunch of EDR? Could I try to slightly over-fire the boiler?

Thanks Steamhead.

Steamhead

The Gortons will make a big difference

If we can vent those lines properly at extremely low pressures, the steam will be as expanded as it can possibly be. This will help it fill the system.

Many Vapor systems were actually orificed so the radiators would only fill to 80% of their capacity. If yours is set up this way, you should be OK. Try the Gortons and see how well it works.

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John Shea

Steamhead

I finally got those Gortons in a couple of weeks ago. Advance plumbing in Detroit is now carrying them!

I was surprised, but they didn't seem to make any difference whatsoever. However, as I may have stated before, I have a hard time creating much pressure at the boiler (I'm not even checking for cracks, holes, etc. in it until spring) which may be the reason there's no improvement.

It got me thinking, though, what was I to do with all those $75 Hoffmans now? Feeling a bit like a mad scientist, I decided to install them on the Vent Traps at the end of the dry returns.

So far, it seems like it made a big impact. There are a few factors that are making it difficult to determine right now (outside temp swings, programmable t-stat changes, etc.) however, the difference in temperature between third floor apartments and first floor apartments is much less, and heat is going where it wouldn't before.

Could this venting be masking a different problem, like restricted wet returns or something?
Or do you think I may be on to something?

After thinking about it extensively, I know that getting the air out of the mains is important, but wouldn't it be just as important to get it out of the radiators AQAP?

Thanks as always.